Explanation:
Touring
the solar system with a 6 year
orbital period, small
comet Hartley 2
(103/P Hartley) will make its closest approach to
planet Earth on October 20 and its closest approach to
the Sun on October 28.
It may become a naked-eye comet, just visible in clear, dark skies.
Meanwhile the comet has been a tempting telescopic target,
seen here with
an alluring green coma as it shares the frame with emission
nebula NGC 281 and stars of
the constellation Cassiopeia on October 2.
The nebula's gaping profile defined by dust clouds against the red
glow suggests its more
playful moniker,
the Pacman Nebula.
An apparent short bright streak shows the comet's motion against the
background stars during the hour of accumulated exposure time.
Over the next few days Comet Hartley 2's motion will also
carry it across
a field of view featuring the famous
double star cluster in Perseus.
On November 4
a spacecraft from planet Earth will
actually fly within about 700 kilometers of
the comet's nucleus.
Now dubbed EPOXI,
that spacecraft was formerly known
as Deep Impact.
